Ключевые слова: blackboard, board, boards, cell phone, cell phones, chalk, chalkboard, connection, connections, contactless, crayon, data, illustration, illustrations, image, mobile payment, mobile payments, mobile phone, mobile phones, mpayment, near field communication, nfc, payment, poster, radiofrequency identification, rfid, security, sign, signs, smartphone, smartphones, social networking, standard, standards, stick, sticks, symbol, symbols, system, systems, ticketing, transaction, transactions, transmission, typography, wallpaper,